Modification of Visible-Light-Responsive Pb2Ti2O5.4F1.2 with Metal Oxide Cocatalysts to Improve Photocatalytic O2 Evolution toward Z-Scheme Overall Water Splitting.

The development of a highly active photocatalyst for visible-light water splitting requires a high-quality semiconductor material and a cocatalyst, which promote both the migration of photogenerated charge carriers and surface redox reactions. In this work, a cocatalyst was loaded onto an oxyfluoride photocatalyst, Pb2Ti2O5.4F1.2, to improve the water oxidation activity. Among the metal oxides examined as cocatalysts, RuO2 was found to be the most suitable, and the O2 evolution activity depended on the preparation conditions for Ru/Pb2Ti2O5.4F1.2. The highest activity was obtained with RuCl3-impregnated Pb2Ti2O5.4F1.2 heated under a flow of H2 at 523 K. The H2-treated Ru/Pb2Ti2O5.4F1.2 showed an O2 evolution rate an order of magnitude higher than those for the analogues without the H2 treatment (e. g., RuO2/Pb2Ti2O5.4F1.2). Physicochemical analyses by X-ray absorption fine-structure spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and time-resolved microwave conductivity measurements indicated that the optimized photocatalyst contained partially reduced RuO2 species with a particle size of ~5 nm. These partially reduced species effectively trapped the photogenerated charge carriers and promoted the oxidation of water into O2. The optimized Ru/Pb2Ti2O5.4F1.2 could function as an O2-evolving photocatalyst in Z-scheme overall water splitting, in combination with an Ru-loaded, Rh-doped SrTiO3 photocatalyst.

Photocatalytic Hydrogen Evolution Activity of Nitrogen/Fluorine-Codoped Rutile TiO2.

The development of a photocatalyst capable of evolving H2 from water under visible light is important. Here, the photocatalytic activity of N/F-codoped rutile TiO2 (TiO2:N,F) for H2 evolution was examined with respect to metal cocatalyst loading and irradiation conditions. Among the metal species examined, Pd was the best-performing cocatalyst for TiO2:N,F under UV-vis irradiation (λ > 350 nm), producing H2 from an aqueous methanol solution. The H2 evolution activity was also dependent on the state of the loaded Pd species on the TiO2:N,F, which varied depending on the preparation conditions. Pd/TiO2:N,F prepared by an impregnation-H2 reduction method, showed the highest performance. However, the activity of the optimized Pd/TiO2:N,F toward H2 evolution from an aqueous methanol solution was negligibly small under visible-light irradiation (λ > 400 nm), although the use of an ethylenediaminetetraacetic acid disodium salt as an electron donor resulted in observable H2 evolution. Transient absorption spectroscopy revealed that although a relatively large population of reactive electrons was generated in the TiO2:N,F under 355 nm UV-pulse photoexcitation, the density of reactive electrons generated under 480 nm visible light was lower. This wavelength-dependent behavior in photogenerated charge carrier dynamics could explain the different photocatalytic activities of the TiO2:N,F catalysts under different irradiation conditions.

Water Oxidation through Interfacial Electron Transfer by Visible Light Using Cobalt-Modified Rutile Titania Thin-Film Photoanode.

TiO2 is a good photoanode material for water oxidation to form O2; however, UV light (λ < 400 nm) is necessary for this system to operate. In this work, cobalt species were introduced onto a rutile TiO2 thin film grown on a fluorine-doped tin oxide (FTO) substrate for visible-light activation of TiO2 and to construct water oxidation sites. TiO2 thin films were prepared on the FTO surface by the thermohydrolysis of TiCl4, followed by annealing at 723 K in air; the loading of the cobalt species was achieved simply by immersing TiO2/FTO into an aqueous Co(NO3)2 solution at room temperature, followed by heating at 423 K in air. Physicochemical analyses revealed that the cobalt species deposited on the TiO2 film was α-Co3(OH)4(NO3)2 and that the cobalt-modified TiO2 thin-film electrode had a visible-light absorption band that extended to 700 nm due to interfacial electron transitions from the cobalt species to the conduction band of TiO2. Upon anodic polarization in the presence of visible light, the cobalt-modified TiO2 thin-film electrode generated an anodic photocurrent with an onset potential of +0.1 V vs RHE, which was consistent with that of pristine rutile TiO2. Product analysis during the controlled potential photoelectrolysis in the presence of an applied bias smaller than 1.23 V under visible light showed that water oxidation to O2 occurred on the cobalt-modified TiO2/FTO. This study demonstrates that a visible-light-driven photoelectrochemical cell for water oxidation can be constructed through the use of earth-abundant metals without the need for a complicated preparation procedure.

Effects of the SrTiO3 support on visible-light water oxidation with Co3O4 nanoparticles.

The photocatalytic activity of SrTiO3 modified with Co3O4 nanoparticles for water oxidation under visible light (λ > 480 nm) was investigated with respect to the physicochemical properties of the SrTiO3 support. SrTiO3 was synthesized by a polymerized complex method or a hydrothermal method, followed by calcination in air at different temperatures in order to obtain SrTiO3 particles having different sizes. Co3O4 nanoparticles, which provide both visible light absorption and water oxidation centers, were loaded on the as-prepared SrTiO3 by an impregnation method using Co(NO3)2 as the precursor, followed by heating at 423 K in air. Decreasing the SrTiO3 particle size (that is, improving the crystallinity) enhanced the photocatalytic activity by promoting the formation of Co3O4 nanoparticles that provided optimal light absorption and catalytic sites. However, Co3O4 aggregation occurred on overly large SrTiO3 particles, leading to a decrease in activity. This study demonstrates the possibility of tuning the photocatalytic activity of a Co3O4-loaded wide-gap semiconductor for visible light water oxidation through the appropriate selection of the support material.

Cobalt Oxide Nanoclusters on Rutile Titania as Bifunctional Units for Water Oxidation Catalysis and Visible Light Absorption: Understanding the Structure-Activity Relationship.

The structure of cobalt oxide (CoOx) nanoparticles dispersed on rutile TiO2 (R-TiO2) was characterized by X-ray diffraction, UV-vis-NIR diffuse reflectance spectroscopy, high-resolution transmission electron microscopy, X-ray absorption fine-structure spectroscopy, and X-ray photoelectron spectroscopy. The CoOx nanoparticles were loaded onto R-TiO2 by an impregnation method from an aqueous solution containing Co(NO3)2·6H2O followed by heating in air. Modification of the R-TiO2 with 2.0 wt % Co followed by heating at 423 K for 1 h resulted in the highest photocatalytic activity with good reproducibility. Structural analyses revealed that the activity of this photocatalyst depended strongly on the generation of Co3O4 nanoclusters with an optimal distribution. These nanoclusters are thought to interact with the R-TiO2 surface, resulting in visible light absorption and active sites for water oxidation.

Bronchial healing after living-donor lobar lung transplantation.

PURPOSE: To review the outcome of bronchial healing after living-donor lobar lung transplantation (LDLLT). METHODS: We retrospectively analyzed 87 anastomoses in 45 consecutive patients who underwent LDLLT, and 14 anastomoses in 10 consecutive patients who underwent cadaveric lung transplantation (CLT), between October 1998 and September 2007. Bronchial anastomosis complications that required intervention were defined as "airway complications" (ACs). RESULTS: There were no significant differences in the background characteristics of the LDLLT and CLT recipients. Airway complications developed in 2 (2.2%) of the 87 anastomoses in the LDLLT group and in 3 (21.4%) of the 14 anastomoses in the CLT group (P = 0.018). The donors of the LDLLT grafts were significantly younger than the donors of the CLT grafts (38.3 years vs 46.1 years, respectively; P = 0.013). The ischemic graft times in the LDLLT and CLT groups were 136.9 min and 413.7 min, respectively (P < 0.0001). The periods of pretransplant ventilation in the LDLLT and CLT groups were 0 days and 4.5 days, respectively (P = 0.0083). CONCLUSION: Our study suggests that bronchial healing after LDLLT is acceptable.

Living-donor lobar lung transplantation and closure of atrial septal defect for adult Eisenmenger's syndrome.

A 38-year-old woman with Eisenmenger's syndrome underwent bilateral living-donor lobar lung transplantation and simultaneous closure of atrial septal defect. The grafts were a right lower lobe from her husband and a left lower lobe from her brother. Although only 2 lobes were implanted, the dramatic improvement in pulmonary hemodynamics has been well maintained for more than 5 years. Living-donor lobar lung transplantation and simultaneous cardiac repair may be one of the therapeutic options for patients with adult Eisenmenger's syndrome with simple congenital heart disease.

Right but not left ventricular function recovers early after living-donor lobar lung transplantation in patients with pulmonary arterial hypertension.

OBJECTIVE: The aim of this study was to evaluate right and left ventricular functions in patients with pulmonary arterial hypertension after living-donor lobar lung transplantation compared with those without hypertension. METHODS: Thirty-three recipients of living-donor lobar lung transplantation were divided into two groups: those with pulmonary arterial hypertension (PAH group; n = 12) and those without (non-PAH group; n = 21). Their systolic pulmonary artery pressure was 93.1 +/- 6.7 mm Hg versus 31.4 +/- 2.9 mm Hg, respectively. Right and left ventricular ejection fractions, systolic pulmonary artery pressure, and cardiac index were serially measured by radionuclide ventriculography and right heart catheterization, respectively. RESULTS: Pretransplant right and left ventricular ejection fractions were lower in the PAH group (29.8% +/- 7.0%, 49.9% +/- 6.6%) than in the non-PAH group (49.7% +/- 3.3%, 65.2% +/- 1.9%) (P = .010, .068). Two months after living-donor lobar lung transplantation, right ventricular ejection fraction and systolic pulmonary artery pressure in the PAH group (57.3% +/- 5.1%, 25.7 +/- 1.8 mm Hg) improved dramatically, equal to those in the non-PAH group. In contrast, left ventricular ejection fraction and cardiac index in the PAH group (50.9% +/- 3.7%, 2.66 +/- 0.12 L x min(-1) x m(-2)) were still significantly lower than in the non-PAH group (65.4% +/- 2.8%, 3.13 +/- 0.15 L x min(-1) x m(-2)) (P = .0038, .037). At 6 to 12 months, the PAH group demonstrated a significant rise in left ventricular ejection fraction and cardiac index that reached similar values in the non-PAH group measured at 2 months. These values were stable for up to 3 years. CONCLUSIONS: Right ventricular function recovered early after living-donor lobar lung transplantation in the PAH group. In contrast, recovery of left ventricular function required 6 to 12 months. Improved cardiac function was sustained for up to 3 years, suggesting long-term durability of cardiac function recovery after living-donor lobar lung transplantation.

Recurrent lung cancer in the mediastinum noticed after a living-donor lobar lung transplantation.

We describe a case of lung cancer in a living-donor lobar lung transplantation (LDLLT) recipient that was identified because of a recurrence in the mediastinum. The patient was a 55-year-old woman who had undergone bilateral LDLLT for nonspecific interstitial pneumonia. She developed dyspnea upon exertion at 15 months after transplantation and was diagnosed as suffering from chronic rejection. A computed tomography scan also revealed enlarged mediastinal lymph nodes (LNs) that were subsequently confirmed as poorly differentiated squamous cell carcinomas. Retrospectively, a small tumor was found in the explanted right lung tissue, the microscopic findings of which were similar to those of the mediastinal lesion. A whole body examination revealed no other lesions; thus we resected the LNs and subsequently irradiated the mediastinum. Recurrent disease appeared in her transplanted lungs 10 months after resection of the LNs, and she died of pneumonia with chronic rejection 2 years and 7 months after transplantation.

Living-donor lobar lung transplantation for pulmonary complications after hematopoietic stem cell transplantation.

BACKGROUND: The indication of lung transplantation for patients with pulmonary complications of hematopoietic stem cell transplantation (HSCT) remains controversial, and only few such cases have been reported. We reviewed our experiences regarding living-donor lobar lung transplantation (LDLLT) in patients with pulmonary complications of HSCT. METHODS: We reviewed and assessed seven patients (age, 6-45 yr) who underwent LDLLT at Okayama University Hospital for pulmonary complications of HSCT (HSCT group). Their characteristics and postoperative results were compared with those of 41 LDLLT without HSCT patients (non-HSCT group). In the HSCT group, indications for LDLLT included bronchiolitis obliterans (n=6) and pulmonary fibrosis (n=1) that had developed after treatments involving HSCT. Preexisting hematologic diseases included acute lymphocyte leukemia (n=4), acute promyelocystic leukemia (n=1), myelodysplastic syndrome (n=1), and aplastic anemia (n=1). RESULTS: In the HSCT group, two patients died due to infectious complications, whereas five are currently alive (an overall survival of 71.4%) without any recurrence of the hematologic diseases (mean follow-up period, 35.7 months). The mean of acute rejection episodes was 1.1 per patient in the HSCT group and 1.8 in the non-HSCT group. One of the seven HSCT (14.4%) and 10 non-HSCT (24.4%) patients have currently developed bronchiolitis obliterans syndrome. CONCLUSION: Our results showed that LDLLT for patients with respiratory failure because of pulmonary complications of HSCT could be an effective approach with less rejection episodes; however, it has a possibly higher risk of the development of infectious complications.

Favorable outcomes after living-donor lobar lung transplantation in ventilator-dependent patients.

PURPOSE: Living-donor lobar lung transplantation (LDLLT) is performed in critically ill patients, although the outcome is generally expected to be poor for those who are ventilator dependent. The aim of this study was to compare the outcomes of LDLLT in ventilator-dependent patients compared with those in ventilator-independent patients. METHODS: We reviewed 31 consecutive patients who received LDLLT between October 1998 and May 2004. RESULTS: Five patients were ventilator dependent and 26 were ventilator independent. All five ventilator-dependent patients were female, with a mean age of 29.6 years. The duration of preoperative ventilation was 23.4 +/- 5.7 days. The underlying diagnoses in the ventilator-dependent patients included only obstructive (n = 3) and infectious lung diseases (n = 2), whereas those in the ventilator-independent patients included hypertensive and restrictive diseases (P = 0.004). There were no significant differences between the groups in early postoperative clinical values. The incidences of acute rejection and bronchiolitis obliterans syndrome (BOS) were comparable. The 5-year survival rates were 100% for the ventilator-dependent patients and 92.3% for the ventilator-independent patients (P = 0.45). CONCLUSION: Our findings suggest that LDLLT can have a favorable outcome in selected ventilator-dependent patients.

Sirolimus ameliorated post lung transplant chylothorax in lymphangioleiomyomatosis.

We report a successful case of sirolimus treatment for chylous pleural and peritoneal effusions of lymphangioleiomyomatosis after lung transplantation. A 32-year-old woman underwent living donor lung transplantation. Persistent chylous pleural and peritoneal effusions were seen postoperatively. Pleurodesis by intrathoracic injection of OK-432, minomycin, and somatostatine analog failed to control chylous effusions. However, sirolimus treatment reduced the amount of chylous drainage and improved both chylous pleural and peritoneal effusions.

Native lung-sparing lobar transplantation for pulmonary emphysema.

The living-donor lobar lung transplantation procedure has been developed clinically as an alternative approach for patients considered too ill to await cadaveric transplantation. With this procedure, 2 lobes are implanted in the recipient in place of whole right and left lungs, respectively. However, the shortage of graft volume can be a problem when compared with full-sized cadaveric grafts. In an attempt to solve this problem, we have developed a native lobe-preserving lobar transplant technique using a large animal model. We report a first successful case of a patient undergoing native lobe-preserving lobar lung transplantation for severe pulmonary emphysema.

Sirolimus amelioration of clinical symptoms of recurrent lymphangioleiomyomatosis after living-donor lobar lung transplantation.

In this study we report the case of a 28-year-old female patient with recurrent lymphangioleiomyomatosis (LAM) in the allografts after bilateral living-donor lobar lung transplantation. Although her post-operative course under immunosuppression with tacrolimus and prednisolone had been uneventful without rejection episodes, she had developed shortness of breath and a progressive chylous effusion with diffuse cystic changes in both lungs 5 years after transplantation. In spite of a diagnosis of having a recurrence of LAM based on radiologic findings and deteriorating pulmonary function, her clinical symptoms, which included dyspnea and chylothorax, were significantly improved after treatment with sirolimus. Although a beneficial effect of sirolimus in the treatment of LAM has not been definitively determined, this report may provide useful information for management of recurrent LAM after lung transplantation.

Current status and potential of living-donor lobar lung transplantation.

Although cadaveric lung transplantation (CLT) offers acceptable prospects for 5-year survival, chronic rejection and donor shortages remain major problems. In an effort to address the donor shortage issue, living-donor lobar lung transplantations (LDLLT) have been performed in some institutions. As of 2006, LDLLT has been performed in approximately 300 patients worldwide. The survival appears to be similar to or better than International Society for Heart and Lung Transplantation registry data on CLT. Because of the possible serious complications after donor lobectomy, LDLLT should be performed only for very sick patients by a well-prepared program. This type of procedure can be applied to restrictive, obstructive, infectious, and hypertensive lung diseases for both pediatric and adult patients who would die soon otherwise.

Living-donor lobar lung transplantation for pulmonary arterial hypertension after failure of epoprostenol therapy.

OBJECTIVES: The aim of this study was to evaluate the long-term effects of living-donor lobar lung transplantation (LDLLT) for critically ill patients with pulmonary arterial hypertension (PAH) who failed in epoprostenol treatment. BACKGROUND: Although continuous epoprostenol infusion has markedly improved survival in patients with PAH, some patients do not benefit from this therapy. METHODS: From July 1998 to December 2003, 28 consecutive PAH patients who were treated with epoprostenol and accepted as candidates for lung transplantation were enrolled. All data were prospectively collected. As of July 2006, LDLLT was performed in 11 of those patients whose condition was deteriorating. Cadaveric lung transplantation (CLT) was performed in 2 patients. Medical treatment was continued in 15 patients. RESULTS: There was no mortality in patients receiving LDLLT during a follow-up period of 11 to 66 months (average 48 months), and all patients returned to World Health Organization functional class I. Mean pulmonary artery pressure decreased from 62 +/- 4 mm Hg to 15 +/- 2 mm Hg (p < 0.001) at discharge and remained normal at 3 years. One CLT patient died of primary graft failure. Among medically treated patients, 6 patients died of disease progression. The survival rate was 100% at 5 years for patients receiving LDLLT, and 80% at 1 year, 67% at 3 years, and 53% at 5 years for patients medically treated (p = 0.028). All living donors have returned to their previous lifestyles. CONCLUSIONS: These follow-up data support the option of LDLLT in patients with PAH who would die soon otherwise.

Long-term improvement in pulmonary function after living donor lobar lung transplantation.

BACKGROUND: As an alternative to cadaveric transplantation, living donor lobar lung transplantation (LDLLT) has been applied in critical patients with end-stage pulmonary disease because of the mismatch between the supply and demand of lungs for transplantation. However, it is unclear whether two pulmonary lobes can provide adequate long-term pulmonary function and satisfactory clinical outcome in recipients. METHODS: Between October 1998 and September 2004, 28 females and 3 males, including 5 children, underwent LDLLT at Okayama University Hospital. Their mean age was 31.8 years, and the mean observation period was 53.8 months. One patient who underwent single-lung transplantation and another who died peri-operatively were excluded from further analyses. RESULTS: The most common indication for transplantation was pulmonary arterial hypertension (32.3%). The overall survival rate was 93.6%. Seven recipients (22.6%) developed bronchiolitis obliterans syndrome after LDLLT. The mean percent predicted forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) improved between 12 and 24 months after transplantation (71.8 +/- 12.9% and 65.8 +/- 17.2% at 12 months vs 77.4 +/- 16.6% and 72.8 +/- 14.6% at 24 months; p < 0.005 and p < 0.05, respectively). The actual recipient FVC ultimately reached 123.0% of the estimated graft FVC of two donor lobes (calculated based on the donor FVC and number of segments implanted) at 36 months after LDLLT. CONCLUSIONS: Although LDLLT may be associated with the limitation of size mismatch, it holds promise for providing well-functioning pulmonary lobar grafts to critically ill patients with poor life expectancy.